I have personally tried to pretty much let the whole MAC Defender trojan thing pass by, since we're not a security website. However, we have an interesting turn of events this week. An article over at Ars Technica quotes several anonymous Apple Store employees as saying that the infection rate of Macs brought into the Apple store has gone up considerably. More interestingly though, Apple's official policy states that Apple Store employees are not allowed to talk about infections to anyone - they're not even allowed to inform Mac owners if they find the infection without the customer's knowledge. Another interesting tidbit: Apple mandates the use of Norton Antivirus on company Macs, according to one Apple Store genius.

Not more than any other company, maybe more than Apple. MS provides an AV because due to the legacy of its terrible security in the recent past, there are many orders of magnitude more Windows viruses, than viruses for any other OS. "

To give Microsoft atleast some credit Microsoft Security Essentials (MSE) is an exceedingly good AV; it's a whole lot less resource-hungry than the others and is very good at doing its job without getting on the nerves of its users. Not to mention it's free.

So while Windows still has a security-hole here or there and Microsoft can't really stop people from being stupid and installing malicious things atleast they are trying to.

As for resource efficient where would you get a reasonable impartial review of AVs? The popular press would have us using McAfee (failed the 4 of the last 5 tests) or Norton. - Well Mac Defender or Norton that would be a tough call

As for resource efficient where would you get a reasonable impartial review of AVs?

That I don't know, I would provide one if I could. My opinion is based on my personal experience; I for example just switched a friend's daughter's laptop to MSE from F-Secure and the speedup was quite noticeable. But I understand that just some random person on the Internets isn't the most reliable source -- it's just anecdotal evidence -- and an impartial review on performance of even 5 of the most used AVs would indeed be nice, even just for the sake of curiosity.

I'll try to remember to PM if I come across one, but all the ones I've seen have been paid for behind-the-scenes.. :/